This invention relates to fluorochemical urethane compositions comprising one or more compounds or oligomers having at least one fluorine-containing repeatable unit and at least one fluorine-containing terminal group. This invention also relates to articles comprising a substrate and the fluorochemical composition, which may be applied as coatings or incorporated as melt additives the fluorochemical compositions impart oil and water repellency to the substrate. In other aspects, this invention relates to processes for imparting oil and water repellency characteristics to substrates and articles.
The use of certain fluorochemical compositions on fibers and fibrous substrates, such as textiles, paper, and leather, to impart oil- and water-repellency and soil- and stain-resistance is well known in the art. See, for example, Banks, Ed., Organofluorine Chemicals and Their Industrial Applications, Ellis Horwood Ltd., Chichester, England, 1979, pp. 226-234. Such fluorochemical compositions include, for example, fluorochemical guanidines (U.S. Pat. No. 4,540,497, Chang et al.), compositions of cationic and non-cationic fluorochemicals (U.S. Pat. No. 4,566,981, Howells), compositions containing fluorochemical carboxylic acid and epoxidic cationic resin (U.S. Pat. No. 4,426,466, Schwartz), fluoroaliphatic carbodiimides (U.S. Pat. No. 4,215,205, Landucci), fluoroaliphatic alcohols (U.S. Pat. No. 4,468,527, Patel), fluorine-containing addition polymers, copolymers, and macromers (U.S. Pat. Nos. 2,803,615; 3,068,187; 3,102,103; 3,341,497; 3,574,791; 3,916,053; 4,529,658; 5,216,097; 5,276,175; 5,725,789; 6,037,429), fluorine-containing phosphate esters (U.S. Pat. Nos. 3,094,547; 5,414,102; 5,424,474), fluorine-containing urethanes (U.S. Pat. Nos. 3,987,182; 3,987,227; 4,504,401; 4,958,039), fluorochemical allophanates (U.S. Pat. No. 4,606,737) fluorochemical biurets (U.S. Pat. No. 4,668,406), fluorochemical oxazolidinones (U.S. Pat. No. 5,025,052), and fluorochemical piperazines (U.S. Pat. No. 5,451,622).
It has long since been well documented that the fluorochemical segment, F(CF2)nxe2x80x94, of essentially any oil- and water-repellency imparting compound, oligomer, or polymer must have six or more carbon atoms; that is n must be equal to or greater than 6 (Philips, R. W. and Dettre, R. H., J. Col. and Interface Sci., 56 (2), (1976)). However, the use of such prior art fluorochemical compositions having fluorochemical segments with n greater than 6, has been cited as a potential concern. Many previously known oil- and water-repellency imparting compounds or oligomers contain perfluorooctyl moieties. These surfactants ultimately degrade to perfluorooctyl-containing compounds. It has been reported that certain perfluorooctyl-containing compounds may tend to bio-accumulate in living organisms; this tendency has been cited as a potential concern regarding some fluorochemical compounds. For example, see U.S. Pat. No. 5,688,884 (Baker et al.). As a result, there is a desire for fluorine-containing compositions which are effective in providing desired oil and water repellency, and/or stain-release or stain resistance properties, and which eliminate more effectively from the body (including the tendency of the composition and its degradation products).
In one aspect, this invention relates to chemical compositions comprising one or more compounds or oligomers and mixtures thereof having at least one fluorine-containing repeatable unit and at least one fluorine-containing terminal group. These compounds or oligomers comprise the condensation reaction product of (a) one or more fluorinated polyols; (b) one or more polyisocyanates; and (c) one or more monofunctional fluorine-containing compounds comprising a functional group that is reactive with the hydroxyl group of said polyol (a) or with the isocyanate group of the polyisocyanate (b), The fluorinated portion of the fluorinated polyol(s) generally comprise at least one fluorine-containing group selected from the group consisting of perfluoroalkyl, perfluoroheteroalkyl, and perfluoroheteroalkylene. Optionally, the fluorochemical compositions further comprise water-solubilizing groups and/or polymerizable groups.
As used herein, the term xe2x80x9coligomerxe2x80x9d means a polymer molecule consisting of only a few, i.e. up to an average of 10, but preferably up to an average of 5, repeating (polymerized) or repeatable units. Each repeating unit comprises a urethane group that is derived from the reaction of at least one polyol and polyisocyanate, wherein at least a portion of the polyol(s) further comprises a fluorine-containing moiety, selected from the group consisting of perfluoroalkyl, perfluoroalkylene, perfluoroheteroalkyl, and perfluoroheteroalkylene. In addition to the fluorinated polyol, the oligomer may further comprise a non-fluorinated polyol. The oligomer is terminated with one or more perfluoroalkyl groups, one or more perfluoroheteroalkyl groups, or mixtures thereof.
Certain preferred embodiments of the fluorochemical compositions of the present invention include those compositions comprising terminal and pendant fluorinated groups having from one to twelve, preferably one to six carbons, most preferably from three to five carbons. Even with Rf groups that are relatively short (i.e. a carbon chain length of less than eight carbon atoms), these fluorochemical compositions, surprisingly, impart excellent oil and water repellency and stain release or stain resistance and exhibit high dynamic water and hexadecane contact angles. Although compositions comprising low fluorine content are less expensive, Rf groups shorter than eight carbons typically have been overlooked by those of skill in the art because they have been believed to impart inferior oil and water repellency and stain resistance.
When the compounds further comprise water solubilizing groups, the fluorochemical compositions of the present invention exhibit water solubility or water dispersability, while at the same time providing surprisingly good water-repellency and stain-release properties. These embodiments include, for example, those chemical compositions comprising a urethane oligomer containing one or more solubilizing groups. The solubilizing groups include carboxylate, sulfate, sulfonate, phosphate, phosphonate, ammonium, quaternary ammonium, and the like, and mixtures thereof. These embodiments are particularly well suited for uniform topical treatments on a variety of substrates where the use of organic solvents is undesirable.
When the compounds further comprise polymerizable groups, the fluorochemical compositions of the present invention exhibit increased durability. That is the repellency and stain-resistant properties remain even after abrasion, scrubbing, washing, exposure to wear, and the like.
Another embodiment of the present invention relates to a coating composition comprising a solution comprising the fluorochemical composition of the present invention and a solvent. In this embodiment, the fluorochemical composition is dissolved or dispersed in the solvent. When applied to a substrate, this coating composition provides a uniform distribution of the chemical composition on the substrate without altering the appearance of the substrate. This invention further relates to a method for imparting water- and oil-repellency, stain-release, or stain-resistance characteristics to a substrate, comprised of one or more surfaces, comprising the steps of:
(a) applying the coating composition of the present invention onto one or more surfaces of the substrate wherein the coating composition comprises:
(i) at least one solvent; and
(ii) the fluorochemical composition of the invention; and
(b) curing the coating composition.
The fluorochemical compositions of the present invention can be applied as coatings to a wide variety of substrates, for example, by topical application, to impart oil- and water-repellency, stain-release, and stain-resistant properties to the substrates. In testing substrates coated with the fluorochemical compositions of the present invention, unexpectedly high dynamic water and hexadecane contact angles have been observed.
When applied as a coating, the coating compositions of the present invention can provide a uniform film. Applied as a coating, the compositions of the present invention do not change the appearance of the substrate to which they are applied. In addition, with certain compositions of the present invention, there is no need for high temperature curing; they can be cured (i.e., dried) at ambient temperature. Some compositions require higher temperature, i.e. up to about 130xc2x0 C.
The fluorochemical compositions of the present invention may also be incorporated with a substrate as a polymer melt blend. The polymer composition comprises one or more thermoplastic or thermoset polymers and the fluorochemical composition of the invention. The present invention also relates to a process for preparing a repellent composition comprising the steps of
(a) combining the fluorochemical composition of the invention; and at least one thermoplastic polymer; and
(b) melt processing the resulting combination.
The present invention further relates to a process for preparing a repellent composition comprising the steps of
(a) combining the fluorochemical composition of the invention; and at least one thermosetting polymer or ceramer or the reactive precursors of said polymer or ceramer; and
(b) curing the resulting combination.
This invention also provides an article comprising a substrate coated or blended with the fluorochemical composition of the invention. After application and curing of the fluorochemical composition on the substrate or melt blending the fluorochemical composition with the substrate, the substrate displays surprisingly high water and hexadecane contact angles which are normally correlated to water- and oil-repellency, stain-release, or stain-resistance properties.
Still further, this invention relates to a method for imparting water- and oil-repellency, stain-release, or stain-resistance characteristics to an article comprising the steps of:
(a) melt blending a fluorochemical composition of the present invention with one or more thermoplastic polymers and
(b) forming the melt blend into an article;
Definitions
Unless otherwise stated, the following terms used in the specification and claims have the meanings given below:
xe2x80x9cAlkoxyxe2x80x9d means a radical xe2x80x94OR where R is an alkyl group as defined below, e.g., methoxy, ethoxy, propoxy, butoxy, and the like.
xe2x80x9cAlkylxe2x80x9d means a linear saturated monovalent hydrocarbon radical having from one to about twelve carbon atoms or a branched saturated monovalent hydrocarbon radical having from three to about twelve carbon atoms, e.g., methyl, ethyl, 1-propyl, 2-propyl, pentyl, and the like.
xe2x80x9cAlkylenexe2x80x9d means a linear saturated divalent hydrocarbon radical having from one to about twelve carbon atoms or a branched saturated divalent hydrocarbon radical having from three to about twelve carbon atoms, e.g., methylene, ethylene, propylene, 2-methylpropylene, pentylene, hexylene, and the like.
xe2x80x9cAralkylenexe2x80x9d means an alkylene radical defined above with an aromatic group attached to the alkylene radical, e.g., benzyl, pyridylmethyl, 1-naphthylethyl, and the like.
xe2x80x9cCured chemical compositionxe2x80x9d means that the chemical composition is dried or solvent has evaporated from the chemical composition from ambient temperature or higher until dryness, up to approximately 24 hours.
xe2x80x9cFibrous substratexe2x80x9d means materials comprised of synthetic or inorganic fibers such as wovens, knits, nonwovens, carpets, and other textiles; and materials comprised of natural fibers such as cotton, paper, and leather.
xe2x80x9cFluorocarbon monoalcoholxe2x80x9d means a compound having one hydroxyl group and a perfluoroalkyl or a perfluoroheteralkyl group, e.g. C4F9SO2N(CH3)CH2CH2OH, C4F9CH2CH2OH, C2F5O(C2F4O)3CF2CONHC2H4OH, c-C6F11CH2OH, and the like.
xe2x80x9cHard substratexe2x80x9d means any rigid material that maintains its shape, e.g., glass, ceramic, concrete, natural stone, wood, metals, plastics, and the like.
xe2x80x9cHeteroacyloxyxe2x80x9d has essentially the meaning given above for acyloxy except that one or more heteroatoms (i.e. oxygen, sulfur, and/or nitrogen) may be present in the R group and the total number of carbon atoms present may be up to 50, e.g., CH3CH2OCH2CH2C(O)Oxe2x80x94, C4H9OCH2CH2OCH2CH2C(O)Oxe2x80x94, CH3O(CH2CH2O)nCH2CH2C(O)Oxe2x80x94, and the like.
xe2x80x9cHeteroalkoxyxe2x80x9d has essentially the meaning given above for alkoxy except that one or more heteroatoms (i.e. oxygen, sulfur, and/or nitrogen) may be present in the alkyl chain and the total number of carbon atoms present may be up to 50, e.g. CH3CH2OCH2CH2Oxe2x80x94, C4H9OCH2CH2OCH2CH2Oxe2x80x94, CH3O(CH2CH2O)nH, and the like.
xe2x80x9cHeteroalkylxe2x80x9d has essentially the meaning given above for alkyl except that one or more heteroatoms (i.e. oxygen, sulfur, and/or nitrogen) may be present in the alkyl chain, these heteroatoms being separated from each other by at least one carbon, e.g., CH3CH2OCH2CH2xe2x80x94, CH3CH2OCH2CH2OCH(CH3)CH2xe2x80x94, C4F9CH2SCH2CH2xe2x80x94, and the like. like.
xe2x80x9cHeteroalkylenexe2x80x9d has essentially the meaning given above for alkylene except that one or more heteroatoms (i.e. oxygen, sulfur, and/or nitrogen) may be present in the alkylene chain, these heteroatoms being separated from each other by at least one carbon, e.g., xe2x80x94CH2OCH2Oxe2x80x94, xe2x80x94CH2CH2OCH2CH2xe2x80x94, xe2x80x94CH2CH2N(CH3)CH2CH2xe2x80x94, xe2x80x94CH2CH2SCH2CH2xe2x80x94, and the like.
xe2x80x9cHeteroaralkylenexe2x80x9d means an aralkylene radical defined above except that catenated oxygen, sulfur, and/or nitrogen atoms may be present, e.g., phenyleneoxymethyl, phenyleneoxyethyl, benzyleneoxymethyl, and the like.
xe2x80x9cHaloxe2x80x9d means fluoro, chloro, bromo, or iodo, preferably fluoro and chloro.
xe2x80x9cLong-chain hydrocarbon monoalcoholxe2x80x9d means a compound having one hydroxyl group and a long chain hydrocarbon group having 10 to 22 carbons which may be saturated, unsaturated, or aromatic, and may optionally be substituted with one or more chlorine, bromine, trifluoromethyl, or phenyl groups, e.g. CH3(CH2)10CH2OH, CH3(CH2)14CH2OH, and the like.
xe2x80x9cPerfluoroalkylxe2x80x9d has essentially the meaning given above for xe2x80x9calkylxe2x80x9d except that all or essentially all of the hydrogen atoms of the alkyl radical are replaced by fluorine atoms and the number of carbon atoms is from 1 to about 12, e.g. perfluoropropyl, perfluorobutyl, perfluorooctyl, and the like.
xe2x80x9cPerfluoroalkylenexe2x80x9d has essentially the meaning given above for xe2x80x9calkylenexe2x80x9d except that all or essentially all of the hydrogen atoms of the alkylene radical are replaced by fluorine atoms, e.g., perfluoropropylene, perfluorobutylene, perfluorooctylene, and the like
xe2x80x9cPerfluoroheteroalkylxe2x80x9d has essentially the meaning given above for xe2x80x9cheteroalkylxe2x80x9d except that all or essentially all of the hydrogen atoms of the heteroalkyl radical are replaced by fluorine atoms and the number of carbon atoms is from 3 to about 100, e.g. CF3CF2OCF2CF2xe2x80x94, CF3CF2O(CF2CF2O)3CF2CF2xe2x80x94, C3F7O(CF3)CF2O)mCF(CF3)CF2xe2x80x94, where m is from about 10 to about 30, and the like.
xe2x80x9cPerfluoroheteroalkylenexe2x80x9d has essentially the meaning given above for xe2x80x9cheteroalkylenexe2x80x9d except that all or essentially all of the hydrogen atoms of the heteroalkylene radical are replaced by fluorine atoms, and the number of carbon atoms is from 3 to about 100, e.g., xe2x80x94CF2OCF2xe2x80x94, xe2x80x94CF2O(CF2O)n(CF2CF2O) mCF2xe2x80x94,
xe2x80x9cPerfluorinated groupxe2x80x9d means an organic group wherein all or essentially all of the carbon bonded hydrogen atoms are replaced with fluorine atoms, e.g. perfluoroalkyl, perfluoroheteroalkyl, and the like.
xe2x80x9cPolyfunctional isocyanate compoundxe2x80x9d or xe2x80x9cpolyisocyanatexe2x80x9d means a compound containing an average of greater than one, preferably two or more isocyanate groups, xe2x80x94NCO, attached to a multivalent organic group, e.g. hexamethylene diisocyanate, the biuret and isocyanurate of hexamethylene diisocyanate, and the like.
xe2x80x9cPolyolxe2x80x9d means an organic compound or polymer with an average of greater than one, preferably two or more primary or secondary hydroxyl groups per molecule, e.g. ethylene glycol, propylene glycol, 1,6-hexanediol, and the like.
xe2x80x9cPorousxe2x80x9d means capable of imbibing a liquid.